In a podcast recorded today, Mullen said North Korea’s nuclear weapon ambitions could lead to instability. He called the country’s alleged test of a nuclear weapon two weeks ago “another example of the belligerence and the ability of North Korea to destabilize the region.”

“From the military perspective, certainly we’ve got a significant capability in the region,” he said, “and our readiness levels are such that it is balanced against the overall requirements there as we watch North Korea.” But he added that diplomacy is the right approach for now. “And that path is the one that everyone’s on,” he said, referring to the United States, the United Nations and a host of American allies.

On Afghanistan, Mullen said Afghan civilians are the “center of gravity” in the counterinsurgency mission there, adding that each civilian casualty “sets us back.” Asked if the United States is planning to change its procedures in response to civilian casualties, Mulled warned against constraining military forces.

“I think we can’t tie our men and women’s hands behind their backs,” he said. “But we’ve got to, from a leadership standpoint, continue to focus on this, make sure we understand the circumstances we’re getting into in the fight, … and absolutely minimize the potential that action could result in civilian casualties.”

Mullen cited a rise in insurgent violence levels in Afghanistan over the past three years, saying that enemy fighters have grown more effective with the aid of safe havens.

“Equally important is the Taliban’s growing allegiance, growing connection to al-Qaida,” he added. “That combination … is a very dangerous one. I am increasingly concerned with the trends.”

The additional U.S. forces deploying to the country are critical to reversing enemy gains, the chairman said.

“Over the next 12 to 18 months, we’ve got to turn the tide to the point where the violence level starts to be reduced and we achieve better security for the Afghan people,” he said.

Mullen remarked on the importance of linking U.S. efforts in Afghanistan and Pakistan under President Barack Obama’s new strategy.

“They are two very distinct sovereign countries, but they really are linked together, and the strategy focuses on defeating al-Qaida, whose headquarters and many members reside in the safe haven in Pakistan,” he said. “So our engagement with Pakistan remains critical.”

Mullen added that steps taken by the Pakistani army in recent weeks to clear out insurgents in the Northwest Province has had significant impact. The clashing has taken enemy fighters off the battlefield and improved Pakistan and, in turn, Afghanistan, he said.

Speaking about the health of the U.S. armed forces, Mullen described the current American military as the best he’s ever served with. He added that multiple and lengthy deployments likely factor into the post-traumatic stress and traumatic brain injuries manifesting in many troops returning home.

“They have sacrificed greatly, they’ve done what we’ve asked them to do as a country, and the American people have been exceptional in supporting them,” Mullen said.

“I believe that in this country there is a sea of good that would reach out and touch and take care of these members and their families, and do it in a way that ensures they have a great life in front of them,” he said. “With what we’ve asked them to do and their sacrifices, I think it’s a debt that we as a country have to pay.”

The chairman emphasized the need for the Defense Department, the Veterans Affairs Department and local communities to work together to coordinate support.